This invention relates to apparatus for the treatment of semiconductors and, more particularly, to apparatus for the treatment of semiconductors in which the undesired deposits formed within the reaction chamber during the vapor phase reaction of semiconductor substrates can be removed easily.
One conventional arrangement for vapor phase silicon, silicon dioxide, silicon nitride, or the like on semiconductor substrates is composed of a reaction chamber, means for heating the semiconductor substrates, and means for introducing a reaction gas into the reaction chamber. With this arrangement, the reaction material is deposited on the semiconductor substrates through the reduction or thermal decomposition of the reaction gas. However, the reaction material is not only deposited on the semiconductor substrates, but also on the heating table, the inner walls of the reaction chamber, and the like. The deposit formed on the heating table must be removed prior to the next cycle of vapor phase, because the semiconductor substrates will not be heated evenly unless the surface bearing them is flat. Moreover, the reaction material deposited on the inner walls of the reaction chamber may fall on the substrates during the reaction so as to cause abnormal growth, or may cloud the inspection window (namely, the window for looking into the reaction chamber) so as to interfere with visual inspection. In order to remove these undesired deposits, a method is available which involves heating the reaction chamber to a high temperature of about 1,000.degree. C. and then introducing a corrosive gas such as HCl into the reaction chamber. However, since this method requires high temperatures of the order of 1,000.degree. C., it is impossible to remove the deposits from the parts which cannot be heated to such high temperatures. Moreover, this method is not applicable to low temperature vapor phase arrangements. Furthermore, the parts which should not be exposed to HCl gas need be cleared of the deposits either by disassembling the apparatus to pickle its components or by using mechanical means to scrape off the deposit.